Charged biomacromolecules

Renard, D. Lavenant-Gourgeon, L. Ralet, M. Sanchez, C. (2006). Acacia Senegal Gum Continuum of Molecular Species Differing by Their Protein to Sugar Ratio, Molecular Weight, and Charges. Biomacromolecules, Vol.7, No.9, (Augudt 2006), pp. 2637-2649, ISSN 1525-7797. 

TABLE 3.9 EiYect of gel pore size on separation of charged biomacromolecules... 

J. Han, C. Zhou, Y. Wu, F. Liu, and Q. Wu, Self-assembling behavior of cellulose nanoparticles during freeze-drying Effect of suspension concentration, particle size, crystal structure, and surface charge. Biomacromolecules 14,1529-1540 (2013). 

Not only will the charge of a lipid and the composition of lipids affect the delivery of biomacromolecules, but the size of the liposome may alter the transport. Mixtures of insulin with three different diameter (1.98 pm, 0.4 pm, and 0.1 pm) neutral liposomes (DPPC Choi) resulted in similar overall hypoglycemic effects to insulin alone. Contrary to this finding is the fact that pulmonary absorption of liposomal [3H] terbutaline, a small molecule, has been reported to be dependent on both composition and size of the liposomes used (Abra et al. 1990). Differences in the absorption mechanism may be the explanation for this contradictory evidence further studies are needed to clarify this and other uncertainties about the uptake mechanism of macromolecules (Patton 1996). 

By nature, the nucleic acid therapeutics have a high negative charge density and are enzymatically labile hydrophilic biomacromolecules thus, efficient delivery of these therapeutics faces similar challenges as the peptide and protein therapeutics. Irrespective of whether the nucleus (in the case of DNA delivery) or the cytoplasm (e.g., for siRNA delivery) of the cell is the intracellular target site, protection and targeting approaches are required to efficiently deliver the drug. 

Harush-Frenkel O, Rozentur E, Benita S, et al. Surface charge of nanoparticles determines their endocytic and transcj4otic pathway in polarized MDCK cells. Biomacromolecules 2008 9 435 3. 

The combination of analytical pyrolysis, molecular modeling, and computational chemistry has also been stressed in investigating the structure of HS. It was reported that computational chemistry which allows to draw, construct and optimize in 3D space biomacromolecules, e.g., aquatic and terrestrial humic substances, with precise bond distances, bond angles, torsion angles, nonbonded distances, hydrogen bonds, charges, and chirality is a powerful tool, and molecular visualization and simulation can also be used to further understand the structure and dynamics of humic and dissolved organic matter. 

The characteristics of biomacromolecules such as solubility, ionic charge, polarity, molecular size, and specificity are utilized in the design of various purification procedures, as shown in Table 3.3. 

Ion-exchange chromatography is generally used in an early stage of biomacro-moleeular purification. It is used to separate neutral biomacromolecules (e.g. neutral polysaccharides) from charged biomaCTomolecules such as nucleic acids versus proteins. 

---